In the past, various pitch adjusting mechanisms for stringed musical instruments have been provided. These pitch adjusting mechanisms generally operate by selectively increasing or decreasing the tension or pitch of a string by moving one of the secured ends of the string to either increase the tension (to raise the pitch) or decrease the tension (to lower the pitch).
These types of pitch adjusting mechanisms have found widespread application on steel guitars. In general, a steel guitar is a generally horizontally mounted guitar having a head end and a tail end and a plurality of strings extending therebetween. The head end is provided with a plurality of tuning keys (one for each string) to which one end of a string is secured. The tuning keys allow adjustment of the pitch of each string to tune the guitar. The other end of the string is secured to a bridge at the tail end of the guitar.
Typical examples of pitch adjusting mechanisms for string instruments, such as a steel guitar, are found in U.S. Pat. No. 3,688,631 and U.S. Pat. No. 3,390,600. These patents are expressly incorporated by reference herein in their entireties. Each of these patents discloses a pitch adjusting mechanism for adjusting the pitch of an individual string both upwardly or downwardly. The mechanisms in both of these two patents also have in common that the pitch adjusting mechanism is provided at the bridge end of the strings and the mechanisms comprise relatively complicated systems of levers, springs and linkages. In order to provide for both raising and lowering the pitch of the string with a single lever attached to the string, these mechanisms provide for a system which allows the single lever to be selectively actuated in both directions, i.e. clockwise and counter-clockwise, and also provide a means for returning the string to the open tune position (this means the normal pitch of the string without actuation of the pitch adjusting mechanism) upon de-actuation. Accordingly, the springs and lever arms of each of the parts of these mechanisms must be delicately balanced to provide proper operation and to minimize or avoid mis-tuning.
Therefore, there is need for a pitch adjustment device for stringed instruments which overcomes the problems associated with prior devices.